docs: def get_region(self, x,z):
          """Get a region using x,z coordinates of a region. Cache results."""
          if (x,z) not in self.regions:
              if (x,z) in self.regionfiles:
                  self.regions[(x,z)] = region.RegionFile(self.regionfiles[(x,z)])
              else:
                  # Return an empty RegionFile object
                  # TODO: this does not yet allow for saving of the region file
                  # TODO: this currently fails with a ValueError!
                  # TODO: generate the correct name, and create the file
                  # and add the fie to self.regionfiles
                  self.regions[(x,z)] = region.RegionFile()
              self.regions[(x,z)].loc = Location(x=x,z=z)
          return self.regions[(x,z)]